modelPartialPlantParallelInterface

Partial model that implements the interface for parallel plants

Extends from Buildings.Fluid.Interfaces.PartialFourPortInterface (Partial model with four ports and declaration of quantities that are used by many models), Buildings.Fluid.Interfaces.FourPortFlowResistanceParameters (Parameters for flow resistance for models with four ports).

Information

This model implements the interface for the parallel plants in the Buildings.Applications.DataCenters.ChillerCooled package. The parallel plants contain num identical plants that share the same temperature setpoint at port_b2. These plants can be operated individually by specifying different on/off signals.

Parameters

TypeNameDefaultDescription
Integernum2Number of equipment
Assumptions
BooleanallowFlowReversal1 (from PartialFourPort)true= false to simplify equations, assuming, but not enforcing, no flow reversal for medium 1
BooleanallowFlowReversal2 (from PartialFourPort)true= false to simplify equations, assuming, but not enforcing, no flow reversal for medium 2
Nominal condition
Modelica.Units.SI.MassFlowRatem1_flow_nominal (from PartialFourPortInterface)Nominal mass flow rate
Modelica.Units.SI.MassFlowRatem2_flow_nominal (from PartialFourPortInterface)Nominal mass flow rate
Modelica.Units.SI.PressureDifferencedp1_nominal (from FourPortFlowResistanceParameters)Pressure difference
Modelica.Units.SI.PressureDifferencedp2_nominal (from FourPortFlowResistanceParameters)Pressure difference
Advanced
Medium1.MassFlowRatem1_flow_small (from PartialFourPortInterface)1E-4*abs(m1_flow_nominal)Small mass flow rate for regularization of zero flow
Medium2.MassFlowRatem2_flow_small (from PartialFourPortInterface)1E-4*abs(m2_flow_nominal)Small mass flow rate for regularization of zero flow
Advanced › Diagnostics
Booleanshow_T (from PartialFourPortInterface)false= true, if actual temperature at port is computed
Flow resistance › Medium 1
BooleancomputeFlowResistance1 (from FourPortFlowResistanceParameters)true=true, compute flow resistance. Set to false to assume no friction
Booleanfrom_dp1 (from FourPortFlowResistanceParameters)false= true, use m_flow = f(dp) else dp = f(m_flow)
Realn1 (from FourPortFlowResistanceParameters)2Flow exponent for side 1, n=1 for laminar, n=2 for turbulent
BooleanlinearizeFlowResistance1 (from FourPortFlowResistanceParameters)false= true, use linear relation between m_flow and dp for any flow rate
RealdeltaM1 (from FourPortFlowResistanceParameters)0.1Fraction of nominal flow rate where flow transitions to laminar
Flow resistance › Medium 2
BooleancomputeFlowResistance2 (from FourPortFlowResistanceParameters)true=true, compute flow resistance. Set to false to assume no friction
Booleanfrom_dp2 (from FourPortFlowResistanceParameters)false= true, use m_flow = f(dp) else dp = f(m_flow)
Realn2 (from FourPortFlowResistanceParameters)2Flow exponent for side 2, n=1 for laminar, n=2 for turbulent
BooleanlinearizeFlowResistance2 (from FourPortFlowResistanceParameters)false= true, use linear relation between m_flow and dp for any flow rate
RealdeltaM2 (from FourPortFlowResistanceParameters)0.1Fraction of nominal flow rate where flow transitions to laminar

Connectors

TypeNameDefaultDescription
Modelica.Fluid.Interfaces.FluidPort_aport_a1 (from PartialFourPort)Fluid connector a1 (positive design flow direction is from port_a1 to port_b1)
Modelica.Fluid.Interfaces.FluidPort_bport_b1 (from PartialFourPort)Fluid connector b1 (positive design flow direction is from port_a1 to port_b1)
Modelica.Fluid.Interfaces.FluidPort_aport_a2 (from PartialFourPort)Fluid connector a2 (positive design flow direction is from port_a2 to port_b2)
Modelica.Fluid.Interfaces.FluidPort_bport_b2 (from PartialFourPort)Fluid connector b2 (positive design flow direction is from port_a2 to port_b2)
Modelica.Blocks.Interfaces.BooleanInput[num]onSet to true to enable equipment, or false to disable equipment

Components

TypeNameDefaultDescription
Medium1.MassFlowRatem1_flow (from PartialFourPortInterface)port_a1.m_flowMass flow rate from port_a1 to port_b1 (m1_flow > 0 is design flow direction)
Modelica.Units.SI.PressureDifferencedp1 (from PartialFourPortInterface)port_a1.p - port_b1.pPressure difference between port_a1 and port_b1
Medium2.MassFlowRatem2_flow (from PartialFourPortInterface)port_a2.m_flowMass flow rate from port_a2 to port_b2 (m2_flow > 0 is design flow direction)
Modelica.Units.SI.PressureDifferencedp2 (from PartialFourPortInterface)port_a2.p - port_b2.pPressure difference between port_a2 and port_b2
Medium1.ThermodynamicStatesta_a1 (from PartialFourPortInterface)if allowFlowReversal1 then Medium1.setState_phX(port_a1.p, noEvent(actualStream(port_a1.h_outflow)), noEvent(actualStream(port_a1.Xi_outflow))) else Medium1.setState_phX(port_a1.p, inStream(port_a1.h_outflow), inStream(port_a1.Xi_outflow))Medium properties in port_a1
Medium1.ThermodynamicStatesta_b1 (from PartialFourPortInterface)if allowFlowReversal1 then Medium1.setState_phX(port_b1.p, noEvent(actualStream(port_b1.h_outflow)), noEvent(actualStream(port_b1.Xi_outflow))) else Medium1.setState_phX(port_b1.p, port_b1.h_outflow, port_b1.Xi_outflow)Medium properties in port_b1
Medium2.ThermodynamicStatesta_a2 (from PartialFourPortInterface)if allowFlowReversal2 then Medium2.setState_phX(port_a2.p, noEvent(actualStream(port_a2.h_outflow)), noEvent(actualStream(port_a2.Xi_outflow))) else Medium2.setState_phX(port_a2.p, inStream(port_a2.h_outflow), inStream(port_a2.Xi_outflow))Medium properties in port_a2
Medium2.ThermodynamicStatesta_b2 (from PartialFourPortInterface)if allowFlowReversal2 then Medium2.setState_phX(port_b2.p, noEvent(actualStream(port_b2.h_outflow)), noEvent(actualStream(port_b2.Xi_outflow))) else Medium2.setState_phX(port_b2.p, port_b2.h_outflow, port_b2.Xi_outflow)Medium properties in port_b2
Modelica.Blocks.Math.BooleanToReal[num]booToReaBoolean to real (if true then 1 else 0)

Revisions

  • June 30, 2017, by Yangyang Fu:
    First implementation.